Published on November 4th, 2011 | by Silvio Marcacci1
Geomembrane Technology Creates Solar-Powered Landfills
energyNOW! visited Conley, Georgia to see how one company is generating renewable energy while safely covering nine million cubic yards of municipal solid waste. You can watch the full video below:
Most people don’t give much thought to the science behind landfills, but they’re a highly engineered environment, designed to safely contain decomposing waste and methane while keeping out the elements. Clean energy advocates have looked at landfills for years as a ideal location for solar power installations, but encountered problems because as waste breaks down over time, their shape can shift and damage solid structures.
Enter the Spectral Power Cap, a first-of-its-kind 45-acre landfill cover combining flexible geomembrane and solar photovoltaic (PV) technology into a dual-purpose system to close the landfill and generate solar energy. The geomembrane is made of thermoplastic polyolefin, similar to the material used on commercial white roofs. It contours to the shape of the landfill and can flex over time, maintaining a snug fit.
The geomembrane is an interesting technology by itself, but what really makes the Spectral Power Cap innovative is the integrated solar panels. About 7,000 flexible 144-watt PV panels are factory bonded to the geomembrane, shipped to the landfill, unrolled on site, and welded together into a solid cover. The PV panels are Teflon-coated, durable enough to walk on, and connected by a million feet of wire to four inverters that sends the solar energy onto the grid.
All in all, the Spectral Power Cap combines four 250-kilowatt arrays covering 10 acres into a total operating capacity of one megawatt, enough to power 224 homes. Best of all, the system makes money for the landfill operators through an agreement with Georgia Power to sell the energy into the wholesale electricity market.
The Conley geomembrane is the largest of its kind, much larger with more generating capacity than two similar installations in New York and Texas, and its success could lead to many more systems across the country. “A lot of these landfills are built in urban settings, and they’re close to transmission lines,” said Tony Walker of landfill operator Republic Services. “We think this type of system can be built across the country.”